Design electroplated coatings

Fig. 11.14 Some design features which will lead to poor distribution and performance of electroplated coatings, and alternatives which will yield satisfactory results...

Reference may be made to BS 4479 Recommendations for the Design of Metal Articles that are to be Coated, Section 2 of which deals with electroplated coatings. 

Plating of a thin iron-phosphorous (Fe-P) layer (2 g/m ) or iron-zinc (3 g/m ) layer on the surface of iron-zinc hot dip or electroplated coatings is also used for automotive applications. The thin electroplated layer is designed to improve formability and to reduce electrocoat cratering tendencies of the iron-zinc alloy coating. 

It will be seen that the design of articles to be electroplated can have a considerable effect on the corrosion resistance of the electrodeposited coating. The chief effects are the result of variations in deposit thickness, but also important are features which can influence the adhesion, porosity and physical properties of the deposit. Good design will also avoid features of the plated article capable of trapping liquids or solid contaminants which might cause more rapid corrosion. 

Yet another option for domestic appliances is to make the appliance from precoated coil. The appliance has to be designed to minimise the problem of unprotected cut edges. Electroplated zinc-coated steel, pretreated, primed and finished with special polyester-melamine, is used. The finish is designed to be hard at room temperature, yet accept bending and forming, probably, but not necessarily, at somewhat higher temperatures (ca. 60°C). 

---